Internet users often receive advertisements in response to their queries, whether directly or alongside other query results that show up as links from which the user may further click to view the content select content. In a paid search advertisement system, advertisers bid on certain search terminology (a “keyword” as used herein, whether it is one or more search terms), so that their advertisement is selected and returned when the user's search keyword is similar to the bidding keyword. A vector-based scoring system is typically used in determining similarity.
However, many times a selected advertisement page is not particularly relevant to the user's query. This is because many advertisers have bid on the same keyword for their corresponding advertisement page. This is bad for both users and advertisers, as users see advertisements that are irrelevant, while advertisers pay for showing advertisements that will not result in business.